Homeland Security officials said Wednesday they will start an “unprecedented” pilot program to test the DNA of families arriving at the U.S. border as soon as next week, calling the measure an investigative tool to root out fraudulent cases of migrants traveling with children who are not their own.

Under the pilot program, Homeland Security investigators can request cheek-swab DNA samples if they suspect that an adult and a minor claiming to be family members do not in fact have a parent-child relationship.

A record number of Central American families have been crossing the southern border with Mexico in recent months, and DHS officials say the migrants are taking advantage of “loopholes” in the U.S. immigration system that enable those arriving with a child to avoid detention and swift deportation.

A private contractor, Ande, which specializes in “rapid DNA” screening for law enforcement and other government purposes, will conduct the DNA tests at the border. Results will be available in two hours, DHS officials said, after which samples and data will be destroyed.

DHS officials said they have detected more than 1,000 cases of fraudulent families trying to cross the border since October, reaching that determination through document screenings and other traditional investigative methods. The agency has been reluctant to introduce DNA testing procedures, in part because of privacy and data storage concerns, officials said.

In some instances, migrant children are paired with uncles, cousins or other relatives who might not be a parent but are part of the same family. But there have been other, more worrisome allegations that some desperate families are accepting payment in exchange for allowing their children to travel with adults who view the minors as an entry ticket to the United States.